Cleese took the stage looking a bit shell-shocked as he gazed out on the audience at the Cleveland Convention Center, quipping that "This dreadful hall looks like a submarine storage bin." He said he had never been to Cleveland before, but that he was sure it would be an only-once-in-a-lifetime experience.

"I'm nervous, because there are 3,200 of you here, from 46 countries, ... and all 3,200 are con-TENT marketers," he deadpanned, pronouncing "content" like the synonym for "satisfied."

"What is content marketing? I should've asked earlier. It's obviously not the opposite of dis-content marketing," he said later.

"I know nothing about marketing. The one thing I know about is creativity," Cleese said. "I think I understand creativity better than anyone else," because all the books about creativity are written by psychologists, "and they're not very creative. I understand it from the inside." He talks about it in his own book, "So Anyway..."

That's despite the fact that "for the first 22 years of my life, no teacher ever noticed that I had a glimmer of creativity." But when he attended Cambridge and met Monty Python-co-founder Graham Chapman, the two began collaborating on comedy sketches.

When Cleese got stuck on how to end a sketch, he would leave it and go to bed. The next morning, when he went back with a cup of coffee, "within two minutes I'd done it," he said. "While I was asleep, my mind had been working on the problem."

Once after he had lost a script, he sat down and rewrote it from memory. When he later found the first draft and compared them, he discovered that "the one that I'd written out from memory was actually quite a bit better than the original." Turns out his unconscious had been rewriting it without his realizing it.

Cleese compared it piano players who know precisely where to place their hands, golfers who always remember how to swing, and drivers who suddenly realize that they have been driving on auto-pilot.

One professor who set out to study creativity among architects went out and interviewed those considered the most creative by their peers, saying: "Tell me what you do, from the moment you wake up in the morning until the moment you go to bed." He then asked the less creative architects the same thing, and discovered only two differences between the two groups: "Creative architects know how to play."

"When you see children play, they're so absorbed," Cleese said. "'What will happen if I pull this wing off? Or these two legs?'" he said, holding an imaginary insect in his fingers. "They're absolutely absorbed."

Likewise, the more creative architects also took much longer to make up their minds about their designs, and refused to be hurried about it. In contrast, most people prefer rushing into decisions, because they don't like leaving things unresolved.

Students at a Chicago art school were once asked to choose items from a table, create still-life arrangements and draw them. While most of the students chose their items quickly and started drawing, a few of them took much longer to pick out their items. "They'd do an arrangement, and rearrange them and rearrange them," Cleese said. Seven years later, the most successful people were the ones who had spent time playing with their objects before drawing them.

John Cleese tells Content Marketing World 2015 that the key to greater creativity lies in awakening and nurturing the unconscious mind.Lisa DeJong, The Plain Dealer

The two different types of thinking are useful for different tasks. A math problem about two trains racing toward each other at different rates of speed is a hare-brained problem, whereas tortoise thinking is better suited for problems involving feelings or psychology, Cleese said. "I'm not denigrating the hare mind, but the tortoise mind is much better for other problems.

"I invented this phrase: 'Get your panic in early.' Don't do nothing for months and then panic," he said. "I want the maximum amount of time. The sooner I start, the sooner it kicks in, and things seem to come together in a way that's almost accidental. Sometimes you don't know when it's going to happen. You can't do that when you're under pressure."

Thomas Edison used to sit in a very comfortable chair next to a metal bowl or plate, holding a handful of ball bearings. He knew that "if he actually dropped off to sleep, the ball bearings would fall onto the plate and wake him up." Edison believed that his brightest ideas came to him in that dreamy, hazy stage when he was half-asleep.

Participants rose to their feet and pulled out their cell phones when John Cleese, the British comedic actor best known for "Monty Python's Flying Circus," took the stage at Content Marketing World 2015.Lisa DeJong, The Plain Dealer

"You've got to start listening to the unconscious, because it's very subtle," Cleese said. "In our society, listening to that subtle stuff is harder than it's ever been before.

"People who are very clear, logically, analytically, they can be absolutely brilliant at that, but they have no capacity for being creative," he said. Just as the grass gets flattened by taking the same path out to the shed, the mind finds it easier to keep taking the same direct shortcut to a task.

"Creativity is getting out of that mental state. If you actually went another way [to the shed] -- just for fun -- you might come across something that wasn't there. You'd get out of a mental rut." Stress can also inhibit creativity, whether it's being under time pressure, having competition, or being interrupted.

Electronic devices demand your time and attention, so it's important to carve out your own creative space. "Don't work in open-plan offices -- Hopeless!" Cleese said. "Sit in the park, quietly, on your own. If you can do that, you've created boundaries of space. Then you have to create boundaries of time."

The first time you try this, "the first thing you think is, 'I should've called Mom.' Or 'Oh crap, I should've gotten a present for my niece.'" He said he keeps little Post-It notes handy, to jot down and clear out whatever's clogging his creative process, so he can think clearly. "Once I started to do that, it all begins to settle. As you get quieter, they'll give you ideas. Notice I said, 'Ideas. I didn't say 'good ideas.'

"After a time, that's when you bring in your local, critical, analytical mind again" to sift through the ideas and figure out what's worth keeping, he said. "Then have another session of being creative. Be really, really original and innovative. It's counter-cultural to go and create your tortoise enclosure, but good luck anyway."

Other Cleese observations from his talk:

-- Teams foster greater creativity if they're not all good at the same things. "Eric Idle is a terrible actor, but a wonderful sketch comedy actor," Cleese said. "I am horrible musically, and so forth.... I used to say to my children, 'If you don't behave yourself, I'll start to sing.'"

-- Cleese is not too fond of Cleveland. "What a dump," he said. "The amazing thing is not that it exists, but that people live here." He liked his hotel here even less.

-- Cleese doesn't like presidential candidate Donald Trump. "Donald Trump? It's not that ours [politicians] are better than yours; it's just that they're a little less awful," he said.

"It's not just that you have no idea what you're doing, but you have no idea that you have no idea," he added. Very smart people understand where they stand in relation to everybody else, but the people who are not as bright think they're fairly clever.

"No wonder nothing works," he said.

His remarks prompted CMWorld founder Joe Pulizzi to clarify after Cleese stepped off the stage that "The City of Cleveland is proud to host the Republican Convention here next year," and that as a bipartisan state, Ohio welcomes politicians from all stripes.